In semiconductor IC manufacturing processes, packaged IC chips may be retested to ensure the electrical characteristics and the functionality. Based on the test results of the electrical characteristics, the IC chips may be classified into different product categories. In addition, the IC chips are subject to visual and mechanical inspection.
The testing of electrical characteristics is intended for measuring various electrical parameters to verify the desired operation of the IC chips.
A conventional two-point contact testing on a same test terminal, for example, Kelvin test, may often include double thimble or double gold finger arranged in parallel. However, there are certain drawbacks as follows.
Low manufacturing precision. The constantly shrinking dimensions of the semiconductor IC chips may cause the shrinking dimensions of the test terminals and the shrinking distances between different test terminals. The precision requirements of the conventional testing such as double thimble or double gold finger arranged in parallel may become too stringent to meet as the dimensions of the test terminals and the distances between different test terminals continue to shrink.
Weak structural strength. In order to achieve the two-point contact on a limited surface of the test terminal, the double thimble or the double gold finger may be made thinner and thinner and accordingly the mechanical structural strength may be weaker and weaker.
Short life span. Testing pins used in the thimble or gold finger testing are often subject to wear and tear. Such wear and tear may be elevated when the high precision requirement weakens the mechanical structural strength. Excessive wear and tear may shorten the life span of testing fixtures.
Low measurement resolution. To accommodate the demand for light weight and small dimension semiconductor IC chips, the constantly shrinking thimble and gold finger dimension may often cause the resistance to increase. When large current measurements are performed, substantial voltage drop may occur and affect the measurement accuracy. On the other hand, the double thimble and double gold finger arranged in parallel may be vulnerable to the displacement deviation between the two testing pins which often produces measurement errors.
Moreover, in order to reduce the distance between the two testing pins, the double thimble arranged in parallel may be configured in a back-to slope contact manner. In such configuration, the testing pins may rotate out of the contact area of the test terminal due to torsion of the spring in the testing fixture. Thus, the measurement accuracy may be affected. Further, the existing testing pins are often unable to perform electrical characteristics testing when the test terminals are in the hemisphere shape.
The disclosed testing probe and semiconductor testing fixture, and their fabrication methods are directed to solve one or more problems set forth above and other problems in the art.